Can anyone suggest if HyperLynx DRC impedance calculations are correct enough to use as regular DRC check? There is very minimal settings in the layer stackup and missing critical information. When I ran impedance DRC, the values are significantly different from the PCB fabrication house calculated. It more matches towards 'Saturn PCB toolkit' calculations.

The impedance calculator is great. The data input might not be so great. What critical information do say is missing? The difference between analysis tool impedance and fabricator impedance calculations is common. The analysis tools such as DRC use the design data. The fabricator knows how they will alter the design data and how their process affects the final geometry. They tweak the design data according to their known process, and that creates slightly different impedances. If you can get the tweak factors from your fabricator then you can adjust the design data such that the analysis tools give the same results as the fabricator.